1. Field of the Invention
The present invention generally relates to a camera apparatus and, more particularly to an exposure control apparatus with shake countermeasure to easily reduce disturbance of hand shaking on an image to be picked up.
2. Description of the Related Art
There has been proposed a technique to permit a shutter release at the peak of hand shaking (where the camera displacement is smallest) in view of hand shaking considered as a simple harmonic motion, thereby minimizing the influence of the shaking of a hand holding a camera on an image to be picked up (hereinafter referred to as "pickup image").
As one example of such a technique, a technique of finding the peak of shaking using a phase shift filter is disclosed in Japanese Unexamined Patent Publication No. 63-53531.
Japanese Unexamined patent Publication No. 64-86122 discloses a technique of substituting a measured shake value into an equation for a simple harmonic motion to acquire a coefficient in order to detect the timing of the next peak of the shaking.
As discussed above, the prior art detects the peak shaking, considering the hand shaking as a simple harmonic motion.
Actually, however, hand shaking is not a simple harmonic motion, but more complicated movement, thus making approximation with simple harmonic motion difficult.
Further, unless there is a minimum measuring time for a half the period between peaks, the next peak cannot be detected, increasing a time lag for shutter release. That is, assuming the frequency of shaking is 2 Hz, the shortest time to detect the next peak is 0.5 sec after the beginning of the measuring.